China's Tesla Risks Overcharging

Tesla Motors isn't the only stock exciting investors about the future of electric cars. Chinese electric-car maker BYD—backed by a major investment from Warren Buffett—has seen its Hong Kong-listed shares soar 153% in the past year, even as Chinese auto stocks are up 66%. This charge could be set to power down.

Investors have gotten excited about BYD thanks both to Tesla's meteoric rise, and because China's central government said...